Device for determining at least one parameter of a flowing medium

ABSTRACT

Devices for measuring at least one parameter of a medium flowing in a line, having an inlet conduit an outlet conduit, having the disadvantage in the prior art that liquids flowing into the inlet conduit can reach a measurement element and alter the measurement characteristic curve behavior of the measurement element. A device of the invention has, between the inlet conduit and outlet conduit, a deflection conduit with a separation element, by which the liquids are separated out and therefore do not reach the measurement element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 35 USC 371 application of PCT/DE 01/01492 filed onApr. 18, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is based on a device for determining at least oneparameter of a flowing medium and on a method for separating a liquidfrom a medium flowing in a line.

2. Description of the Prior Art

A device with a measurement conduit is already known (German PatentDisclosure DE 197 35 891 A1) in which a measurement element isaccommodated that is bathed there by the inflowing medium. The mediumflows from an inlet conduit first into a deflection conduit, which has alarger flow cross section than the inlet conduit and has a right-angledcorner, so that there is an abrupt flow transition in the form of a stepto the inlet conduit. Next, deflected by the corner of the deflectionconduit, the medium flows along the peripheral face of the deflectionconduit into an outlet conduit adjoining it transversely and leaves theoutlet conduit through an outlet opening and then mixes again with themedium flowing past the device.

An inlet conduit longitudinal axis and an outlet conduit longitudinalaxis are inclined by a predetermined angle from the longitudinal axis ofthe line, so that the inlet conduit has a region that is shaded from amain flow direction. The measurement element is disposed in the shadedregion of the measurement conduit, to prevent soiling and resultantdefects in the measurement element.

Water entering the intake line, for instance if the roadway is wet withrain, can sometimes cause contamination of the measurement element.Natural components of dissolved salts contained in this splashing waterthen cause a drift in the characteristic curve of the measurementelement, because of the formation of a salt crust on the diaphragm ofthe sensor part. Although the inclination of the measurement body doesform a partitioned-off region, nevertheless liquid particles reach themeasurement conduit.

From German Patent Disclosure DE 197 41 031 A1, a measuring device withan inlet conduit is known in which a speeding up of the flow in theinlet conduit can be maintained by the design of two walls of the inletconduit, but it is known that this leads only to stabilizing the flow ofthe medium in the inlet conduit, in particular in the measurementconduit.

SUMMARY OF THE INVENTION

The device and method according to the invention have the advantage overthe prior that a measurement element is protected against liquid in asimple way.

It is advantageous to embody a liquid separation element in a conduit atleast partly in labyrinthine fashion, because in this way liquid can beseparated out yet liquid from the outside cannot penetrate into theconduit.

It is advantageous to embody the liquid separation element in an innerwall of a deflection conduit of the device, because this improves theseparation.

Internested annular-arclike elements, which are simple to produce from atechnical standpoint, are an advantageous embodiment of the liquidseparation element.

It is advantageous to increase the flow resistance of the liquidseparation element compared to the flow resistance of a measurementconduit, because as a result the great majority of the gaseous componentof the flowing medium remains in the measurement conduit.

It is also advantageous to provide a deflection conduit in the inletconduit that deflects the flow from the inner wall, because thedeflection of the flow is facilitated thereby.

For good separation of liquid, it is advantageous that there is adetachment edge in the deflection conduit, which prevents depositedwater from moving in the form of a wall film into the measurementconduit.

To stabilize the measurement signal, it is advantageous that the flowcross section of the inlet conduit and/or the outlet conduit narrows inthe flow direction.

BRIEF DESCRIPTION OF THE DRAWING

Exemplary embodiments of the invention are explained in further detailin the ensuing description, taken with the drawings, in which:

FIG. 1 is a fragmentary elevation view, partly in section, of a deviceaccording to the invention;

FIG. 2 is a detail of a section through FIG. 1;

FIG. 3 is a section taken along the line III—III of FIG. 2;

FIG. 4 is a section taken along the line IV—IV of FIG. 2; and

FIG. 5 is a further exemplary embodiment of the device of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 schematically shows how a device 1 of the invention isincorporated in a conduit or line 3 within which the medium, which is agas-liquid mixture, flows.

The device 1 comprises a measurement housing 6, represented by a lowerrectangle drawn in dot-dashed lines, and a carrier housing 7,represented by an upper rectangle drawn in dot-dashed lines, in whichlatter housing an electronic evaluation unit, for instance, isaccommodated. The measurement housing 6 and carrier housing 7 can mergeintegrally with one another or can be individual parts that are joinedtogether. The measurement housing 6 and the carrier housing 7 have acommon longitudinal axis 10, which can for instance also be a centeraxis. The carrier housing 7 for instance protrudes partway out of theline 3.

The measurement housing 6 has a side face 8, which is located in theplane of the drawing.

The device 1 is introduced, for instance in plug-in fashion, into a wall15 of the line 3. The plastic or metal wall 15 defines a flow crosssection, in the center of which a center axis 16 extends in thedirection of the flowing medium, parallel to the wall 15. The directionof the flowing medium, hereinafter called the main flow direction, isindicated by corresponding arrows 20 and extends from left to right inthe drawing.

FIG. 2 shows the plan view on the measurement housing 6 in a sectionalplane parallel to the plane of the drawing in FIG. 1, with a conduit 22that has an inlet conduit 24 into which the medium flows through aninlet opening 25. There is an inlet conduit flow direction 29 in theinlet conduit 24. Disposed at the end of the inlet conduit 24 is adeflector element 33, which deflects the flow from an inner wall into adeflection conduit 40, which causes a detachment downstream and improvesa phase separation of the individual mixture components. In thedeflection conduit 40, the flowing medium is deflected and flows into anoutlet conduit 44, which at least in part also forms a measurementconduit 47. An outlet conduit flow direction 50 prevails in the outletconduit 44. In the measurement conduit 47, the medium flows past atleast one measurement element 60, which is disposed on a sensor carrier56. At the end of the outlet conduit 44, the medium strikes an outflowelement 51, as a result of which the medium is deflected and thus flowsback into the line 3. By means of the outflow element 51, the flowdirection of the medium in the outlet conduit 44 is rotated at leastpartway around the longitudinal axis 10. The medium emerging through atleast one outlet opening 53 (FIG. 4) then flows approximately in themain flow direction 20. This improves the measurement signal performancein the case of reverse flows.

The outlet opening 53 or the outlet conduit 44 can, however, also bedesigned as in DE 197 41 031 A1, which is hereby incorporated byreference.

Disposed in the deflection conduit 40 on its outer periphery is aseparation element 70, which is embodied, for instance on its inner wall41 facing in the main flow direction 20, in labyrinthine fashion. Theseparation element 70 has at least one separation inlet 64 and at leastone separation outlet 68, which connect the deflection conduit 40 withthe line 3 and through which a liquid separated out at the wall passesout of the deflection conduit 40 into the line 3.

To prevent too much gas from leaving the inlet conduit 24 through theseparation element 70, the flow resistance of the separation element 70is increased over that of the inlet conduit 24 and outlet conduit 44.

A sharp outflow edge 73 is disposed in the inlet conduit 24 or in thedeflection conduit 40, for instance on the deflector element 33; thisedge prevents a liquid, such as water, deposited on a lower side wall 42of the inlet conduit 24 from participating in the deflection in themeasurement conduit 47 in the form of a wall film in the direction ofthe measurement element 60. The wall film detaches at the outflow edge73 from the side wall 42 of the inlet conduit 24 and is entrained by theflow. Because of the greater inertia of the liquid compared to the gas,the liquid strikes the inner surface of the outer wall 41 of thedeflection conduit 40, for instance, where it can form a wall filmagain. This wall film migrates through the separation inlet 64 into theseparation element 70 and leaves it through the separation outlet 68into a rear chamber 71. The medium that is deflected in the deflectionconduit 40 and forced against the inner wall 41 by centrifugal forcespushes the wall film into the separation inlet 64 in the process. At anupper side wall 43 of the inlet conduit 24, which is opposite the lowerside wall 42, for instance, the wall film need not detach from the sidewall but instead is pushed directly into the separation inlet 64.

Liquids in the conduit 22 that do not form any wall film strike theinner wall 41 and are thereby separated out of the conduit 22.

The labyrinthine separation element 70 for instance comprises threeannular-arc elements 76, which are internested. At least one shunt 79 isdisposed in the region of the separation outlets 68 and protects againstwater or liquid entering from the line 3.

FIG. 3 shows a section taken long the III—III of FIG.

The conduit 22 narrows in the inlet conduit 24 in the flow direction 29,so that a stabilization of the flow takes place.

The rear chamber 71, on the side face 8 along the longitudinal axis 10,has slits 72 through which the liquid that has been separated outreturns to the conduit 3, in which the liquid no longer causes anynegative effects.

FIG. 4 shows a section taken along the line IV—IV of FIG. 2.

The outlet conduit 44 also narrows in the outlet conduit flow direction50. Once the flowing medium has flowed past the sensor carrier 56 withthe measurement element 60, it strikes the outflow element 51. Theoutflow element 51 is embodied in the shape of a W, for instance, anddeflects the outlet flow direction 50, so that the medium, through atleast one outlet opening 53, enters the line 3 again and flows onward inthe main flow direction 20 again. In this exemplary embodiment, thereare two outlet openings 53.

The outflow element 51 protrudes past a side face 54 of the measurementhousing 6. The primary flow 3 creates a negative-pressure zone(detachment) at the outflow element 51 in the region of the outletopening 53 and thus exerts suction on the flow in the measurementconduit 44. Because the outflow element 51 protrudes past the side fact54, a reverse flow that is present in some phases is fed into themeasurement conduit 44 and measured.

FIG. 5 shows a further exemplary embodiment of the device 1 of theinvention. The difference from the exemplary embodiment of FIG. 2 isessentially that the outlet conduit 44 is the closest to the carrierhousing 7, and the inlet conduit 24 is disposed on a lower end of themeasurement housing 6. Also, the sensor carrier 56 has two measurementelements 60, which measure the volumetric flow and the pressure, forinstance.

The foregoing relates to preferred exemplary embodiment of theinvention, it being understood that other variants and embodimentsthereof are possible within the spirit and scope of the invention, thelatter being defined by the appended claims.

What is claimed is:
 1. A device (1) for determining at least oneparameter of a medium flowing in a line (3) in a main flow direction(20), the medium comprising a gas-liquid mixture, the device comprising:a measurement housing (6) in the line (3); a conduit (22) that isdisposed in the measurement housing (6) and has the followingproperties: the conduit (22) being divided into an inlet conduit (24), adeflection conduit (40), and an outlet conduit (44) and having an inletopening (25), which is adjoined by the inlet conduit, which in turn isadjoined by the deflection conduit (40), into which the medium flowsfrom the inlet conduit (24) and is deflected, and then flows through theoutlet conduit (44) to at least one outlet opening (53), discharginginto the line (3) at an outer face (8, 54) of the measurement housing(6), one part of the conduit (22) forming a measurement conduit (47), atleast one measurement element (60) that is located in the measurementconduit (47) and is bathed by the flowing medium, and a liquidseparation element (70) integrated with the deflection conduit (40),said liquid separation element (70) is embodied at least in part inlabyrinthine fashion and has at least one separation inlet (64) and atleast one separation outlet (68).
 2. The device of claim 1, wherein theliquid separation element (70) is embodied in the region of an innerwall (66) of the deflection conduit (40).
 3. The device of claim 1,wherein the flow resistance of the liquid separation element (70) isincreased compared to the flow resistance of the measurement conduit(47) due to the change in contouring.
 4. The device of claim 1 whereinthe device (1) has the measurement housing (6) and a carrier housing(7); wherein the measurement housing (6) and the carrier housing (7)have a longitudinal axis (10); wherein the inlet conduit (24) and theoutlet conduit (44) are disposed one above the other along thelongitudinal axis (10); and wherein the inlet conduit (24) is theclosest to the carrier housing (7).
 5. The device of claim 1 wherein aflow cross section of the inlet conduit (24) narrows in the flowdirection (29) toward the deflection conduit (40).
 6. The device ofclaim 1 wherein the flow cross section of the outlet conduit (44)narrows in the flow direction (50) toward the outlet opening (53). 7.The device of claim 1 wherein at least one part of the inlet conduit(24) and at least one part of the outlet conduit (44) extend inclinedrelative to the main flow direction (20).
 8. The device of claim 1wherein The flow direction of the medium in the outlet conduit (44) isrotated at least partway around the longitudinal axis (10).
 9. Thedevice of claim 1, wherein the gas-liquid mixture is aspirated air foran internal combustion engine.
 10. A device (1) for determining at leastone parameter of a medium flowing in a line (3) in a main flow direction(20), the medium comprising a gas-liquid mixture, the device comprising:a measurement housing (6) in the line (3); a conduit (22) that isdisposed in the measurement housing (6) and has the followingproperties: the conduit (22) being divided into an inlet conduit (24), adeflection conduit (40), and an outlet conduit (44) and having an inletopening (25), which is adjoined by the inlet conduit, which in turn isadjoined by the deflection conduit (40), into which the medium flowsfrom the inlet conduit (24) and is deflected, and then flows through theoutlet conduit (44) to at least one outlet opening (53), discharginginto the line (3) at an outer face (8, 54) of the measurement housing(6), one part of the conduit (22) forming a measurement conduit (47), atleast one measurement element (60) is located in the measurement conduit(47) and is bathed by the flowing medium, and a liquid separationelement (70) integrated with the deflection conduit (40), said liquidseparation element (70) is embodied in the region of an inner wall (66)of the deflection conduit (40).
 11. The device of claim 10 wherein thedevice (1) has the measurement housing (6) and a carrier housing (7);wherein the measurement housing (6) and the carrier housing (7) have alongitudinal axis (10); wherein the inlet conduit (24) and outletconduit (44) are disposed one above the other along the longitudinalaxis (10); and wherein the inlet conduit (24) is the closest to thecarrier housing (7).
 12. The device of claim 10 wherein a flow crosssection of the inlet conduit (24) narrows in the flow direction (29)toward the deflection conduit (40).
 13. The device of claim 10 whereinthe flow cross section of the outlet conduit (44) narrows in the flowdirection (50) toward the outlet opening (53).
 14. The device of claim10 wherein at least one part of the inlet conduit (24) and at least onepart of the outlet conduit (44) extend inclined relative to the mainflow direction (20).
 15. The device of claim 10, wherein the gas-liquidmixture is aspirated air for an internal combustion engine.
 16. A device(1) for determining at least one parameter of a medium flowing in a line(3) in a main flow direction (20), the medium comprising a gas-liquidmixture, the device comprising: a measurement housing (6) in the line(3); a conduit (22) that is disposed in the measurement housing (6) andhas the following properties: the conduit (22) being divided into aninlet conduit (24), a deflection conduit (40), and an outlet conduit(44) and having an inlet opening (25), which is adjoined by the inletconduit, which in turn is adjoined by the deflection conduit (40), intowhich the medium flows from the inlet conduit (24) and is deflected, andthen flows through the outlet conduit (44) to at least one outletopening (53), discharging into the line (3) at an outer face (8, 54) ofthe measurement housing (6), one part of the conduit (22) forming ameasurement conduit (47), at least one measurement element (60) islocated in the measurement conduit (47) and is bathed by the flowingmedium, and a liquid separation element (70) integrated with thedeflection conduit (40), said liquid separation element (70) is formedby at least two internested annular-arclike elements (76).
 17. Thedevice of claim 16 wherein the device (1) has the measurement housing(6) and a carrier housing (7); wherein the measurement housing (6) andthe carrier housing (7) have a longitudinal axis (10); wherein the inletconduit (24) and outlet conduit (44) are disposed one above the otheralong the longitudinal axis (10); and wherein the outlet conduit (44) isthe closest to the carrier housing (7).
 18. The device of claim 16wherein a flow cross section of the inlet conduit (24) narrows in theflow direction (29) toward the deflection conduit (40).
 19. The deviceof claim 16, wherein the gas-liquid mixture is aspirated air for aninternal combustion engine.
 20. A device (1) for determining at leastone parameter of a medium flowing in a line (3) in a main flow direction(20), the medium comprising a gas-liquid mixture, the device comprising:a measurement housing (6) in the line (3); a conduit (22) that isdisposed in the measurement housing (6) and has the followingproperties: the conduit (22) being divided into an inlet conduit (24), adeflection conduit (40) and an outlet conduit (44) and having an inletopening (25), which is adjoined by the inlet conduit, which in turn isadjoined by the deflection conduit (40), into which the medium flowsfrom the inlet conduit (24) and is deflected, and then flows through theoutlet conduit (44) to at least one outlet opening (53), discharginginto the line (3) at an outer face (8, 54) of the measurement housing(6), one part of the conduit (22) forming a measurement conduit (47), atleast one measurement element (60) is located in the measurement conduit(47) and is bathed by the flowing medium, and a liquid separationelement (70) integrated with the deflection conduit (40), the devicefurther comprises a deflector element (33) in a downstream end of theinlet conduit (24).
 21. The device of claim 20, further comprising adetachment edge (73) on the deflector element (33).
 22. The device ofclaim 20, wherein the gas-liquid mixture is aspirated air for aninternal combustion engine.